Using code snippets as 'functions' of sorts in a web developer's IDE?

ok so this is somewhat of an awkward question, but lets put it 开发者_Python百科like this...

I have a website with about 15 pages... Thanks to HTML5, I have a distinct and for the site. The content in these sections is fairly complex (with navigation menus and what not).

Now here's the problem, on Monday, (when I completed the site) everything was fine. On Wednesday, I realized that I need to add another item to the navigation menu in the , and change the parameters of some elements in the ...

Any simplistic way of doing this, other than editing one file, and then copy/pasting into each and every other file manually one by one?

Is there a good IDE out there that will allow me to just add a as a snippet in many places, and if I edit the master snippet, it auto-changes everywhere else?

Hope I'm being clear here...

Well… first thought: is server side scripting out of question? If so, maybe server side includes can be utilized? Whichever IDE you'd use, it'd solve only part of the problem, leaving real architectural problem untouched.